package teste;

/*
 * @(#)HeapSortAlgorithm.java	1.0 95/06/23 Jason Harrison
 *
 * Copyright (c) 1995 University of British Columbia
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL purposes and without
 * fee is hereby granted provided that this copyright notice
 * appears in all copies. Please refer to the file "copyright.html"
 * for further important copyright and licensing information.
 *
 * UBC MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. UBC SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 */

/**
 * A heap sort demonstration algorithm SortAlgorithm.java, Thu Oct 27 10:32:35
 * 1994
 * 
 * @author Jason Harrison@cs.ubc.ca
 * @version 1.0, 23 Jun 1995
 */
public class HeapSortAlgorithm extends SortAlgorithm {
	public void sort(int a[]) throws Exception {
		int N = a.length;
		for (int k = N / 2; k > 0; k--) {
			downheap(a, k, N);
		
		}
		do {
			int T = a[0];
			a[0] = a[N - 1];
			a[N - 1] = T;
			N = N - 1;
		
			downheap(a, 1, N);
		} while (N > 1);
	}

	private void downheap(int a[], int k, int N) throws Exception {
		int T = a[k - 1];
		while (k <= N / 2) {
			int j = k + k;
			if ((j < N) && (a[j - 1] < a[j])) {
				j++;
			}
			if (T >= a[j - 1]) {
				break;
			} else {
				a[k - 1] = a[j - 1];
				k = j;
				
			}
		}
		a[k - 1] = T;
		
	}
}
